1. Field of the Invention
The present invention generally relates to an insulation bobbin of a stator and, more particularly, to an insulation bobbin of a stator that provides a larger room for radial windings.
2. Description of the Related Art
Referring to FIG. 1, Taiwanese Patent No. 525869 discloses a conventional insulation bobbin 9 of a stator of a DC motor. The insulation bobbin 9 includes a body 91 and a plurality of extension members 92. The body 91 includes a hole 911 from which the extension members 92 extend outwards radially. Each extension member 92 has an accommodation room 921 whose cross section resembles a “□” shape. The accommodation room 921 has an opening and two protruding clamp 922 located on two edges of the opening.
When the insulation bobbin 9 is coupled with a silicon steel plate unit 8, the accommodation rooms 921 may accommodate a plurality of salient-poles 81 of the silicon steel plate unit 8, in which a plurality of pole faces 82 of the silicon steel plate unit 8 extends outside the accommodation rooms 921. Based on this, each protruding clamp 922 may have a top face abutting against a bottom face of an individual salient-pole 81 so that a bottom face of the protruding clamp 922 is spaced from the bottom face of the salient-poles 81 by a distance. With the distance, a metallic coil C can be kept away from the salient-poles 81 during the winding process.
In general, when the extension members 92 are wound with more turns of the metallic coil C, the DC motor will have stronger magnetic fields and larger rotation torque. In order to improve the structural strength of the insulation bobbin 9, the portion of the extension member 92 around which the metallic coil C is wound usually has the same thickness T. As a result, less turns of the metallic coil C can be wound around the extension members 92 in an axial direction of the DC motor. In light of this problem, the thickness of the extension member 92 may be reduced to increase the number of turns of the metallic coil C. However, this reduces the structural strength of the extension members 92, causing the extension members 92 to be easily damaged during assembling and winding processes.
Therefore, it is desired to improve the conventional insulation bobbin 9.